Process for coating pyrotechnic materials

Abstract

A method for preparing the surface of pyrotechnic propellant compositions for coating by emersing said compositions in an aqueous/alcohol solution.

What is claimed is: 
     
       1. A method of treating the surface of a pyrotechnic propellant material prior to application of a coating on said material which comprises etching the surface of the material with a solution comprised of about 1 to 10 vol. % water and 99 to 90 vol. % of a C 1  to C 4  aliphatic alcohol for an effective amount of time. 
     
     
       2. The method of claim 1 wherein the C 1  to C 4  alcohol is selected from the group consisting of methanol, ethanol, and isopropanol. 
     
     
       3. The method of claim 2 wherein the solution consists of about 2 to 4 vol. % water and 98 to 96 vol. % alcohol. 
     
     
       4. The method of claim 3 wherein the pyrotechnic propellant is in pellet form. 
     
     
       5. The method of claim 1 wherein the pyrotechnic material is comprised of an inorganic oxidizer, an oxygen-containing polymeric compound, and a coolant. 
     
     
       6. The method of claim 5 wherein the inorganic oxidizer is sodium chlorate, the oxygen-containing polymeric compound is a polyacetal resin, and the coolant is calcium hydroxide. 
     
     
       7. The method of claim 1 wherein the pyrotechnic material is comprised of an alkali or alkaline earth metal azide and a metal oxide. 
     
     
       8. The method of claim 7 wherein the alkali-metal azide is sodium azide and the metal oxide is iron oxide.